Steam shower Construction

Discussion in 'Shower & Bathtub Forum & Blog' started by dradam, Sep 30, 2008.

  1. dradam

    dradam New Member

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    I am building a steam shower an have had to sort through a lot of conflicting information on the web. I know many like kerdi or nobleseal but the inside membranes seem like extra cost, more pieces or strips to leak and more work to install (two layers of thinset). I am looking for feedback on my current plan.

    I have an acrylic base and ceiling that are preformed and steam compatible so For the walls I am planning..

    2x4 stud walls

    pvc or cpe membrane over the 2x4 will go inside the lip of the acrylic ceiling and base sealed to the lip top and bottom

    1/2 inch durock over the cpe or pvc membrane

    unfortified thinset joints mid wall, but silicone joints between wall panels and between walls and ceiling /base to allow for expansion.

    unfortified thinset and grout to adhere my tile with white silicone at ceiling/base and wall junction to allow for expansion.

    Based on what I have read having the vapor/moisture barrier outside the enclosure is ok as long as the thinset and grout are not latex modified as this would trap moisture beneath the tile.


    Thank you
     
  2. geniescience

    geniescience Homeowner

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    Sounds good. Very thorough work. Congratulations.

    -david
     
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Having the waterproofing underneath means that you will have a huge amount of moisture IN the tile and walls. A recipe for mold. You really want a surface membrane and there are probably 3-4 that are approved for this. I don't know if you can view the specifications on-line for free, or have to buy the book, but the TCNA (Tile Council North America) sets the standards for tile use in showers, and on floors (well, basically everywhere you could reasonably put tile). These form the basis of acceptable industry standards. Many areas base the building codes on them by reference. Don't try to roll your own - go to the source. They've tested and know what works. It's a major expense building a steam shower; might as well do it so it will last and perform well.
     
  5. dradam

    dradam New Member

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    what is your recommended inside treatment -Kerdi?
     
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Personally, I like Kerdi. Latticrete and Noble both make good surface waterproofing systems as well. In my view, the less you can saturate with moisture the better. This requires a surface membrane, not one embedded further inside the steam shower. Attention to detail is paramount - you don't want any of that moisture to get into the wall system. While not a big deal in a conventional shower, all of the nail or screw holes required to install CBU on top of a membrane means numerous holes. The vapor pressure drives moisture deep within the structure in a steam shower. It isn't any where near as big a problem in a conventional one. This means sealing every penetration - steam head, valves, etc. carefully and well. A steam shower is a very different animal than a conventional shower. A Sloped ceiling is also very useful since you don't want cold drips of condensation falling on you while you are lounging in the steam, either.

    If you haven't visited www.johnbridge.com, you should. You'll get the straight, well-qualified line of help there from tiling pros that have more than one steam shower under their belts. TCNA defines more than one way to correctly build a steam shower...pick one, and stick with it. Don't try to mix systems or invent your own.
     
  7. dradam

    dradam New Member

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    thank you very much
     
  8. theshowerguy

    theshowerguy New Member

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  9. jla

    jla New Member

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    My contractor will be beginning my master bath renovation shortly and I am having a Thermasol Pro-Series steam shower installed. After reading your posts, I am concerned that the proper steps may be inadvertently overlooked in the steam shower installation since it is not a common project in this area. How do I make sure that the proper steps are followed as well as the proper supplies, especially barriers, membranes, mortars, etc. are used? Is there a specific check list of steps detailing all of this? I'd rather be extra careful now and not have any future problems.
     
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    See if your local library has a copy of the latest (2012) version of the TCNA handbook - Tile Council of North America, if not, you can buy one directly from them. In there, they list and describe all industry approved and tested ways to build a successful steam shower. If your contractor followed one of the approved methods AND used good workmanship without errors or omissions, it should be okay. This isn't something people should wing on their own - lots of engineering and historic testing results have gone into developing methods that work.
     
  11. jla

    jla New Member

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    Thank you both so much for the good information. I am hoping to do a play-by-play on this blog if I can figure out what they're doing without bothering the workers too much.
     
  12. jla

    jla New Member

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    Concerning the tile inside the steam shower, the only thing I know is that I am using ceramic on the walls, porcelain on the floor and seat and an accent of some glass tiles. They are all from different manufacturers. I would have thought that Thermasol would know about the thinset. Must these tile manufacturers be contacted?
    Also, I did mention the TCNA book to my contractor. He did not seem to be aware of it but will check into it.
     
  13. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    FWIW, porcelain IS a ceramic. My preference would be to use porcelain tile in a steam shower since it absorbs less that conventional ceramic tile. A good porcelain will only absorb 1-2%, some ceramic tile can absorb 10x as much and the resulting time to dry out.
     
  14. jla

    jla New Member

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    I just read the info above that the tile in a steam shower should be porcelain. Does everyone feel this way?
     
  15. jla

    jla New Member

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    That link says, "virtually all tiles work well..." but to discuss with a representative. Do you recommend I change my shower wall and ceiling selection to porcelain? It has not been ordered yet so if you think it's important, I will do that.
     
  16. jla

    jla New Member

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    Actually it's a glazed ceramic which I was just told is ok.
     
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The reasons why porcelain and glass are preferable is that they don't absorb much moisture (often less than 1%). Not all ceramics are created equal, and on many ceramic tile, the glaze does not cover the edges all the way so moisture can wick in from the edges up to the range of 10-20%. This can cause the tile to change color as the ceramic absorbs moisture. Just like porcelain is a ceramic, the construction techinque and materials used in generic ceramic tiles differ, so some may exhibit this, and others may not. If you can get a sample piece, stand it up on edge in about 1/2" of water overnight and see what it looks like. See how far, if at all, moisture wicks up into the tile and look for color changes on the face.

    A quality porcelain normally would not show this effect. Some ceramic tiles will. Some of this depends on how long and often the steam shower is used, and how well it can dry out in between.
     
  18. jla

    jla New Member

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    So after only a few hours in the 1/2" of water, the water on the BACK of the glazed ceramic tile "wicked" halfway up. Is this what you mean is not good? You are right about the glaze not being on the edges.
     
  19. jla

    jla New Member

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    And how do I know what a "quality" porcelain tile is?
    On another issue, my steam shower and tub are on the same outside wall. Should the slanted ceiling in the steam shower continue for the length of that wall so also be over the tub?
     
    Last edited: Aug 22, 2012
  20. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Vapor pressure will push that moisture into the walls. Depending on how long the steam shower is used, how well the room is ventillated, and how often, eventually, it can saturate the walls and you'd see a potential color change in the tile beneath the grout.

    You may need to dig for it, but read the spec sheets for any porcelain you may be interested in. Something that has a <1-2% absorbtion rate should be fine - almost all are. Some ceramics can absorb 10-20% or more.

    To work, the steam shower is likely enclosed, so you'd not need to slope that entire area.
     
  21. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    If you care to see my thoughts, rather than copying them here, http://www.terrylove.com/forums/sho...r-System-s-new-shower-ready-made-niches/page5 post #67.

    Short answer...Schluter does not recommend Kerdiboard for commercial steam showers for a reason. It's not in their manual on shower construction. Why John is trying to compare the product in an area it is not recommended with some that are is making a skewed point. Using tools or products in manners they were not intended should have no reflection on how well they work for areas in which they can excel.
     
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